var async = require("async");

async.series(
    {
      method1: function(callback){
         console.log("this is method1 function");
          //传递给下一个函数
         callback(null, 1);
      },
      method2: function(callback){
          callback(null, 2.1, 2.2);
      },
      method3: function(callback){
          console.log("this is method3 function");
          callback();
      }

    },

    function(err, results){
        console.log(results);
    }
);